Proteins can change over time to adapt to new challenges, but this can sometimes affect their original function. In this study, scientists looked at how mutations in certain proteins affected their ability to resist antibiotics. They found that as the proteins evolved, the interactions between mutations became more important. This means that as proteins adapt, they become less stable and more sensitive to changes. This trade-off is a cost of adaptation that can have big effects on how proteins work. This research gives us a better understanding of how proteins change and evolve, and the trade-offs involved in developing new functions.